Group III-V nitride semiconductors have been variously applied to an optical device such as blue and green Light Emitting Diodes (LED), a high speed switching device such as a Metal Oxide Semiconductor Field Effect Transistor (MOSFET), a High Electron Mobility Transistor (HEMT) and a Hetero junction Field Effect Transistor (HFET), and a light source of a lighting device or a display device.
The nitride semiconductor is mainly used for the LED or a Laser Diode (LD), and studies have been continuously conducted to improve the manufacturing process or light efficiency of the nitride semiconductor.